Protein digestion



April 14, 1942 G. B. AYRES ETAL. 2,279,909

PROTEIN DIGESTION original Filed'June 16, 1959 /o/L/ of ag/'aeszzz'O/z I ATTORNEY.

Patented Apr. 14, 1942l --uNl'rED STAT-Es PATENT ori-fics PROTEIN DIGESTION American Cyanamld Company, New N. Y., a corporation of Maine Conn.,

Original application June 16, 1939, Serial No.

4 Claims.

The invention relates the controlled diges# tion of protein materials and more particularly 'to the bating of hides and skins by subjecting processes involving the selective digestion of proteins.

It is an object of the present invention tov provide these enzymes in the form of a dried proteolytic culture which is suitable for use as a bate. y

It is a further object to provide a method for the bating of hides and skins using these enzymes as bates, preferably in conjunction with a deliming agent such as ammonium sulfate.

' The invention includes both the production of these enzymes from Pem'cillz'um camemberti by inoculation of a suitable nutrient medium and Divided and this application ber 9, 1939, Serial No. 303,555

Novem-l cultivation of the inoculated medium and the provision of the enzymate (enzyme-i-c'arrier) in dried form, and also the selective digestion 0125 proteins and the bating of hides and skins by subjecting the materials to the action of these proteolytic enzymes. i

As illustrative of the proteolytic activity in alkaline solution of these enzymes produced by Penicillium camemberti" thereris shown in the single ligure of the accompanying drawing a this curve that the enzymes oi' the present invention manifesta uniformly good rate of activity in alkalies at least up to the point where the alkalinity reaches a pH value of about l9.5.

'I'he preparation of these enzymes is as follows: A suitable nutrient medium in the granular or solid discrete particle condition, such as bran, moistened with an equal weight of water, is inoculated with afculture of Penicillium camemberti and the inoculated n'ioist bran spread out in thin layers on trays. The inoculated bran is then incubated in an oven maintained at a temperature .of about 30 C. and preferably vat not higher than this temperature, and at a humidity in the oven such that the atmosphere therein issaturated butvdoes not contain sufficient moisture to cause deposition of the same onto the bran. The inoculated bran is maintained in the oven until sporulation occurs. After incubationy for the optimum period the bran culture may be thoroughly mixed with 0.2% of cresylic acid in solution, if desired, to improve the wetting out of the bran when used in solution. The culture or enzymate is then dried at a temperature below C., e. g., 40 C., and may be` used as such for hating,` or an ammonium salt, e. g., ammonium sulfate, maybe incorporated with the moist mass and the mixture then dried. The bran used f or the culture may or may not be sterilized before the inoculation and likewise the culture may or may not be sterilized, although sterilization of the culture or enzymate does not appear necessary at the present time.

The enzyme may be liberated from the dried culture by elution with dilute solutions of various salts, such as ammonium, chloride, ammonium sulfate, sodium chloride, sodium sulfate, etc., and the eluted enzymes used in other fields as digestants. v 'I'he proteolytic enzymes may be applied to the bating of hides and skins in the form of an en,

proteolytic activity of enzymes described -in the pH of 10. By inspection it will be seen from l zymate in any manner now practiced in the art for the application of other tryptic bates. One

-method now in use involves washing the hides from the deharing step, and adding an ammonium salt, such as ammonium sulfate, to the water containing the hides in order to lower their pH which. is generally very high due to the strongly alkaline conditions under whichl dehairing takes place. Before'adding the ammonium salt the hides may be treated for removing lime blast by the addition of a suitable acid, such as hydrochloric acid, to the water bath containing the hides. After the pH of the bath-has been suitably adjusted, the enzyme bate is added thereto in an amount determined by the enzyme unit strength of the bate, the kind of hide or skin to be bated. the extent of bating desired, the length o! the bating time and the temperature of the hating-bath.

For purposes of illustration, there is described in the following example a method for bating of hides with the enzymes of Penicillium camembert.

Example Wash a. 500 1b. pack of limed kips from the dehairing 4bath with water for 15 minutes at 70 F. Heat the washed pack in water to 95 F. and add 5 lbs. of hydrochloric acid thereto, the bath showing red to methyl orange. After three minutes add lime to the bath until it is slightly pink to phenolphthalein. To the bath then add 31/2 ibs. of ammonium sulfate and about 1% (based on the weight of the kips) of enzymate'prepared as described above. Run the paddle for the desired length o f bating time with a final temperature therein of 85 F. After the kips have been bated cool them to 70 F.

' While thel application of these enzymes has been described with particular reference to the bating of hides and skins their utility is not limited tothis eld. On the contrary they may be used in many other processes in which a tryptic enzyme of high activity is desired, such as in desizing and degumming textiles, paper sizing, tenderizing of meat, stripping of gelatin from photographic films and plates, manufacture of peptones, chewing gum, glue, foods, drugs and biological products or in any eld where by their use a protein or a protein degradation product can be reduced to a lower molecular size of increased solubility.

It will be understood that the above description is intended as illustrative 'and not as limiting of the invention, the scope of which is defined by the following claims.

This is a division of our copending application Serial No. 279,471-, vfiled June 16, 1939.

What we claim is:

- 1. A process of bating hides which comprises subjecting them to the action of enzymes present enzymes of Penicillium camemberti in a dried culture of the mold, said enzymes being characterized by a uniformly high rate of proteolytic activity under alkaline conditions within a pH range up to about 9.5.

3. A process of bating hides whichcomprises subjecting them to the action of enzymes of Pen-icillium camemberti n a dried culture of the mold, said enzymes being characterized by a uniformly high rate of proteolytic activity under alkaline conditions within a pH range up to about 9.5, and in the presence of an ammonium salt.

4. A process of bating hides which comprises subjecting them to the action' of enzymes of Pemcillium camemberti in a dried culture of the mold, said enzymes being characterized by a uniformly high rate of proteolytic activity under,l

GILBERT B. AYRES. JOSEPH G. NIEDERCORN. 

